2of 2Authorities say evidence in the car Ebel was driving also link him to a pizza deliveryman's slaying.

DECATUR — Shell casings from a Texas shootout with a white supremacist Colorado parolee are the same make and caliber as those found at the home of Colorado's prison chief after he was killed, according to legal papers.

It's the closest link yet between Evan Spencer Ebel — who died in the shootout — and the slaying of Tom Clements, who was shot and killed when he opened his door Tuesday.

Authorities also say they found a Domino's pizza bag and a jacket or shirt in the trunk of the car Ebel was driving when Texas deputies tried to pull him over — a link to another slaying, that of a pizza deliveryman whose body was found Sunday.

In a case that's been confusing in how the suspect is connected to each crime, the search warrant documents released Friday in Texas brought some clarity.

Ebel, 28, is a Colorado parolee with a long record of convictions since 2003 for various crimes including assaulting a prison guard in 2008.

He was a member of a white supremacist prison gang called the 211s, a federal law enforcement official said.

Colorado officials wouldn't confirm Ebel's gang ties or say whether they had anything to do with the death of prisons director Tom Clements. But they locked down prisons Friday for the second time since Clements' slaying without stating the reason, and said state troopers are providing extra security for Colorado government officials.

“We are at a heightened alert,” said Steve Johnson of the Colorado Bureau of Investigation.

Denver police said they were “confident” Ebel was involved in the death of Nathan Leon, 27, the pizza man whose body was found Sunday.

They've been less forthcoming about his link to Clements' death, aside from saying the car Ebel was driving during the shootout in Texas is similar to one seen at Clements' home the night of the shooting.

Ebel fired at Texas authorities who tried to stop him Thursday. The .9 mm Hornady casings found after the Texas shootout match those found at Clements' house, Texas Ranger Anthony Bradford wrote in the application for a search warrant.

Authorities said they were running ballistics tests to see if they could conclusively link the gun Ebel used in Texas with the one that killed Clements.

The FBI and local officials also were beginning to examine another case that appears similar to the Clements killing — the Jan. 31 slaying of a prosecutor in Kaufman — about 100 miles from where Ebel crashed and got into the shootout. Mark Hasse was gunned down as he walked across a parking lot to the courthouse.

Authorities have investigated whether Hasse's death could be linked to a white supremacist gang. On Friday, they said they will see if there is any connection to Clements' murder.

“This is part of routine investigative work when two crimes occur under somewhat similar circumstances,” Kaufman Police Chief Chris Aulbaugh said.

Ebel's tie to Clements' killing comes from the car he drove — a black Cadillac with mismatched Colorado plates that fit the description of a vehicle spotted outside Clements' home just before the prison chief answered his front door and was shot to death.

Texas authorities spotted the car Thursday and gave chase after Ebel shot and wounded a deputy. They fatally shot him after he crashed into a semi and opened fire on his pursuers.

Ebel isn't on the radar of the Southern Poverty Law Center, which tracks extremist groups, but the center rates the gang as one of the most vicious white supremacist groups operating in the nation's prisons, comparable to the Aryan Brotherhood of Texas.